Coverage of 2006 International
Conference on AIDS

August 14–18, 2006, Toronto, Canada

 

The KLEAN Study, ACTG 5095

Martin Delaney, Founding Director, Project Inform
August 17, 2006

One interesting study reported at Toronto compared a regimen based on the GlaxoSmithKline protease inhibitor, Lexiva (fosamprenavir/ritonavir), to the “gold standard” regimen based on Kaletra (lopinavir/ritonavir) from Abbott Labs. The regimen with Kaletra has for some time now been one of only two regimens highly recommended by the Federal Guidelines for treating people just beginning therapy (the other is a regimen containing Sustiva [efavirenz]). While there is little doubt that the regimen with Kaletra is both highly potent and very durable, it has not been directly compared to a number of other regimens. This study sought to determine whether a regimen containing Lexiva was at least not inferior to the Kaletra regimen.

The study included 878 people taking either Kaletra or Lexiva together with Epzicom.. (Epzicom isa combination tablet with Ziagen [abacavir] + Epivir [3TC, lamivudine].) People who experienced an allergic reaction to abacavir (about 6%) were allowed to switch to a different drug.

After 48 weeks, the percentage of people who had undetectable viral load (under 50 copies) was virtually identical in the two group, though a slightly higher percentage of those on Lexiva regimens had viral loads below 400 copies. Median gain in CD4+ cell counts was also very similar between the two groups, with the Lexiva group gaining 176 cells and the Kaletra group gaining 191. Drug-related adverse events were also similar in both groups, as was the number of people who stopped therapy due to adverse events.

Researchers who conducted the study concluded that using Lexiva was not inferior to using Kaletra. It would be equally accurate to state that the two regimens appeared to be equal in this patient population. One of the major benefits claimed for using Kaletra in other studies is that it results in very long-term stability on therapy. Because this study only followed people for 48 weeks, there is no way to directly compare Kaletra and Lexiva regimens in terms of long-term results. However, there was also no indication of any kind that would suggest there would be a difference in long-term follow-up.

The importance of this study for people just beginning therapy is that Lexiva represents a third reasonable alternative, thus giving people greater choice. However, it will take some time before this finding is reflected in the Federal Treatment Guidelines. The overall significance of this study is somewhat moderated by another study reported at the conference which compared a similar Kaletra regimen against a Sustvia-based regimen. For more information about this study, see the related article, “Kaletra vs Sustiva vs a Combination of the Two.”